334 SWIFTS . 
Long after the light has faced from the western horizon we may hear 
this voice from the starlit heavens, for the Nighthawk is one of our few 
truly nocturnal birds. Occasionally the peents are given more rapidly, 
and after calling several times in close succession the bird on half-closed 
wings dives earthward with such speed that one fears for his safety; but 
just before the ground is reached he checks his rapid descent by an 
abrupt turn, and on leisurely wing again mounts upward to repeat this 
game of sky-coasting. At the moment the turn is made one may hear a 
rushing, booming sound, which, as writers have remarked, can be imi- 
tated in tone by blowing across the bung-hole of an empty barrel. It 
is made by the passage of the air through the bird’s primaries. 
In late summer Nighthawks gather in large flocks and begin their 
southward migrations. When flying the white mark on their primaries 
is a conspicuous character, and has the appearance of being a hole in 
the bird’s wing. 
1905. Herrick, F. H., Home-Life of Wild Birds, 129-135. 
420b. C. v. chapmani Cowes. Fioripa NicutHawk. Similar to the 
preceding, but smaller, and with the white and cream-buff markings of the 
upperparts more numerous. L., 8°60; W., 7°10; T., 4°10. 
Range.—Breeds in the Gulf coast belt from eastern Tex. to Fla.; winter 
range unknown. 
Nesting date, Volusia Co., Fla., May 8. 
420c. C. v. sennetti Coues. Szennetr’s NicntHawx. Palest of our 
Nighthawks; whitish prevailing in wing coverts and scapulars; less rufous 
than in C. v. henry; less heavily barred below than C. »v. virginianus. W., 
710. 
Range.—Breeds on treeless plains from Sask. and Man. s. to cen. Nebr.; 
he aaa in Iowa, Wisc., and Ills.; winter range unknown, probably in 
45. Famity Micropopis. Swirts. (Fig. 56.) 
The ninety-odd known species of Swifts are distributed throughout 
the greater part of the world but are most abundant in the tropics. 
About one-third this number are American but only four advance north 
of Mexico. Some Swifts nest in colonies and most species are associated 
in companies, at other times of the year. Hollow trees and caves are the 
natural nesting- and roosting-places of many species, while others fasten 
their nests to the under surface of palm leaves, and the East Indian 
Tree Swifts attach their nest to a limb. Most Swifts appear to employ 
the glutinous secretion of the salivary glands in nest-construction and 
the edible nests of the Swifts of the genus Collocalia are composed 
entirely of this substance. 
Swifts lay white eggs and the young are naked when hatched. They 
feed entirely while flying, and with their unusually long wings and small, 
compactly feathered bodies possess unrivaled powers of flight. Swifts 
are popularly confused with Swallows, but the resemblance is only 
superficial and exists chiefly in the similarity of flight and feeding 
